Piperidine derivatives as photostabilizer

ABSTRACT

Disclosed is a piperidine derivatives of a formula: ##STR1## wherein R 0  indicates a hydrogen atom or a group R--CO) n  where R is an alkyl, alkylene or arylene group capable of having 1 to 4 carboxylic group; 
     R 1  indicates a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an acyl group having 2 to 7 carbon atoms, or an arylalkyl group having 7 to 10 carbon atoms; 
     R 2  and R 2&#39;   respectively indicate a hydrogen atom, or an alkyl group having 1 to 4 carbon atoms; 
     R 3  and R 4  in combination indicate a group ═CH--R 5 , or R 3  indicates a hydrogen atom and R 4  indicates either --CH 2  --R 5  wherein R 5  is a substituted or non-substituted phenyl group or a substituted or non-substituted cyclohexyl group the substituent being an alkyl having 1 to 4 carbon atoms, or a 2-furyl group or a tetrahydrofuryl group; and 
     n indicates an integer of 1 to 4. 
     The piperidine derivatives are improved photostabilizer to various organic materials including poly-α-olefins with least breeding out tendency.

This is a division of application Ser. No. 07/893,021, filed on Jun. 3,1992 now U.S. Pat. No. 5,189,172 issued on Feb. 23, 1993.

BACKGROUND OF THE INVENTION

1. Field of the Art

The present invention is concerned with piperidine derivatives of anovel structure.

More particularly, the present invention relates to2,2,6,6-tetraalkylpiperidine derivatives which are useful asphotostabilizers/lightstabilizer or as intermediates therefor and arealso usable as intermediates for pharmaceuticals and agriculturalchemicals.

2. Related Art

It has heretofore been known in the art that chemical compounds having a2,2,6,6-tetraalkylpiperidine structure, viz. what is called hinderedamine structure, have capability of capturing radicals at a high level,whereby these compounds have been used as photostabilizers for variousorganic materials, particularly resins.

The most typical hindered amine compounds having the photostabilizingcapability may be 2,2,6,6-tetramethyl-4-piperidinol of a formula (1)which is often and hereinbelow abbreviated as TMPNL: ##STR2##

Most commercially available photostabilizers are derivatives of TMPNL inthat it is used as an intermediate and is processed to have a highermolecular weight by, e.g. condensation with a polybasic carboxylic acid.For instance, as shown in Y. Nakahara et al: RECENT DEVELOPMENT INADDITIVES FOR HIGH POLYMERS (in Japanese), C.M.C. Corp. 1988,bis(2,2,6,6-tetramethyl-4-piperidyl)sebacate which is a representativephotostabilizer known to have high photostabilizing capability to a lotof resins and hereinbelow referred to as LS770 is an ester of TMPNL withsebacic acid of a formula: ##STR3##

While the TMPNL derivatives representable by LS770 have highphotostabilizing capability, they may have disadvantages such that theyeasily breed out from resin compositions to which they have been addedwhereby it may be difficult to use them in resin compositions for use asthin articles such as film, and even when they are used in resincompositions for use as thick articles, the surface of the articles maybe deteriorated by the breeding out whereby coatability of the articlesis deteriorated.

In order to solve these problems, various piperidine derivatives haveheretofore been synthesized, such as a piperidinone derivative disclosedin Japanese Patent Publication No. 42987/1979 having a formula: ##STR4##wherein R⁰ is a phenyl group or a 2-furyl group.

The compound of formula (3) may have some disadvantages, as long as thepresent inventors know, such that it may be difficult to process it tohave a higher molecular weight and the resin compositions having thecompound added as a photostabilizer may be discolored when thecompositions are fabricated.

SUMMARY OF THE INVENTION

The object of the present invention is to solve the problems inherent inthe TMPNL derivatives shown above by presenting novel TMPNL derivativesmodified in a specific way.

The present invention thus present a piperidine derivative of a formula:##STR5## wherein:

R⁰ indicates a hydrogen atom or a group R--CO)_(n) where R is an alkyl,alkylene or arylene group capable of having 1 to 4 carboxylic group;

R¹ indicates a hydrogen atom, an alkyl group having 1 to 4 carbon atoms,an acyl group having 2 to 7 carbon atoms, or an arylalkyl group having 7to 10 carbon atoms;

R² and R^(2') respectively indicate a hydrogen atom, or an alkyl grouphaving 1 to 4 carbon atoms;

R³ and R⁴ in combination indicate a group ═CH--R⁵, or R³ indicates ahydrogen atom and R⁴ indicates--CH₂ --R⁵ wherein R⁵ is either asubstituted or non-substituted phenyl group or a substituted ornon-substituted cyclohexyl group the substituent being an alkyl having 1to 4 carbon atoms, or a 2-furyl group or a tetrahydrofuryl group; and

n indicates an integer of 1 to 4.

The piperidine derivatives in accordance with the present invention havean aromatic ring in the molecule and thus have a higher solubility thanthe piperidine derivatives of the prior art in various organic materialsincluding resins, such as polyolefins, e.g. polyethylene, polypropyleneand polystyrene and a lower discoloring activity when they are kneadedwith resins such as given above, whereby they are advantageously used asa photostabilizer as such or, when they are of a low molecular weightwhere R⁰ is a hydrogen atom, as derivatives endowed with a highermolecular weight by esterification with mono- or polybasic carboxylicacid (other than R--COOH)_(n)) with high photostabilization capabilitywithout entailing the breeding out.

The piperidine derivatives in accordance with the present invention hasa hydroxyl group when R⁰ is a hydrogen atom and an amino group when R¹is a hydrogen atom, and it may be easy for converting the piperidinecompounds into further derivatives in utilization of the hydroxyl and/oramino group.

The piperidine derivatives having substituents R³ and R⁴ in accordancewith the present invention may have higher resistance to hydrolysis thanthe similar compounds having, however, no R³ and R⁴ substituents formedin most of conventional photostabilizers including TMPNL and LS770.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. A1 is a ¹ H-NMR spectrum for3-benzyl-2,2,6,6-tetramethyl-4-piperidinol, Compound A1 prepared inExample A1;

FIG. A2 is a ¹³ C-NMR spectrum by the proton decoupling method for3-benzyl-2,2,6,6-tetramethyl-4-piperidinol, Compound A1 prepared inExample A1;

FIG. B1 is ¹ H-NMR spectrum for3-cyclohexylmethyl-2,2,6,6-tetramethyl-4-piperidinol, Compound Bprepared in Example B1;

FIG. B2 is a ¹³ C-NMR spectrum by the proton decoupling method for3-cyclohexylmethyl-2,2,6,6-tetramethyl-4-piperidinol, Compound B1prepared in Example B1;

FIG. C1 is ¹ H-NMR spectrum forbis(3-cyclohexylmethyl-2,2,6,6-tetramethylpiperidine-4-yl) sebacate,Compound C15 prepared in Example C1;

FIG. C2 is a ¹³ C-NMR by the proton decoupling method forbis(3-cyclohexylmethyl-2,2,6,6-tetramethylpiperidine, Compound C15prepared in Example C1; and

FIG. C3 is an IR absorption spectrum forbis(3-cyclohexylmethyl-2,2,6,6-tetramethylpiperidine-4-yl) sebacate,Compound C15 prepared in Example C1.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION Outlineof the Compounds

The piperidine derivatives in accordance with the present invention arerepresented by a formula [I] given hereinabove, and are thus classifiedinto two classes.

The compounds of the first class are those of the formula [I] where R⁰is R--CO)_(n), which are thus piperidinols.

The compounds of the second class are those of the formula [I] where R⁰is R--CO)_(n), which are thus esters of the piperidinols.

The piperidine derivatives in accordance with the present invention,irrespective of whether they are classified in the first or secondclass, have an amino group which is secondary where R¹ is H or istertiary where R¹ is not H, whereby they can be in their salts.

It is thus to be understood that the term "piperidine derivatives"includes the derivatives in their salts, especially addition salts.Examples of acids to form the salts include inorganic acids, such ashydrohalogenic acids such as, e.g. hydrochloric acid; sulfuric acid, andphosphoric acid; and organic acids, such as lower alkane mono- ordicarboxylic acids such as formic acid, acetic acid, oxalic acid, andsulfonic acids such as toluenesulfonic acid.

The piperidine compounds in accordance with the invention of coursepossess reactivity as an alcohol, when R⁰ is H, such as esterificationto form esters, wherein the compounds of formula [I] in accordance withthe present invention are an example of the esters.

Piperidinols

The piperidinols may also be classified into two sub-classes.

The piperidinols of the first sub-group are those of the formula [I]where R³ and R⁴ contain unsaturation.

The piperidinols of the second sub-group are those of the formula [I]where the unsaturation in R³ and R⁴ of the first sub-group ishydrogenated.

In either group, the piperidinols of the formula [I] where R⁰ is H arepreferably those of the formula [I] where R^(2') is H.

1) The piperidinols of the first sub-group

The piperidinols of the formula [I] where R³ and R⁴ contain unsaturationof the first sub-group are those of the formula [I] where R³ and R⁴ incombination indicate a group ═CH--R⁵ or R³ indicates a hydrogen atom andR⁴ indicates a group --CH₂ --R⁵, where R⁵ indicates an unsubstituted orC₁ -C₄ alkyl-substituted phenyl group, or a 2-furyl group, R¹ and R²being defined above, and R^(2') being H.

The piperidinols of the first sub-class are those where R¹ -R⁵ are asfollows.

R¹ is either one of a hydrogen atom, an alkyl group of 1 to 4 carbonatoms such as methyl and n-butyl, an acyl group of 2 to 7 carbon atomssuch as acetyl and benzoyl, or arylalkyl group of 7 to 10 carbon atomssuch as benzyl and 1-phenylethyl. R¹ is preferably a hydrogen atom or amethyl group from the viewpoint of production of the compounds, althoughall the R¹ s referred to above may provide the compounds with improvedphotostabilizing capability.

R² is either one of a hydrogen atom, or an alkyl group of 1 to 4 carbonatoms such as a methyl group and a n-butyl group. R² is preferably ahydrogen atom or a methyl atom, a hydrogen atom being more preferable.

R³ and R⁴ are either one of (a) R³ is a hydrogen atom and R⁴ is a group--CH₂ --R⁵ or (b) R³ and R⁴ are in combination to form a group ═CH₂--R⁵, where R⁵ is a phenyl group, C₁ -C₄ o-, m- or p-alkyl-substitutedphenyl such as a p-tolyl phenyl and p-t-butylphenyl or a 2-furyl group.R³ and R⁴ are preferably such that (i) R³ is a hydrogen atom and R⁴ is abenzyl, (ii) R³ is a hydrogen atom and R⁴ is a furfuryl, (iii) R³ and R⁴in combination indicate a benzylidene group, or (iv) R³ and R⁴ incombination indicate furfurylidene group, and the compounds where R³ isa hydrogen atom and R⁴ is a benzyl group are more preferable.

Examples of the piperidinols of the first sub-class include:

(1) 3-Benzyl-2,2,6,6-tetramethyl-4-piperidinol, Compound A1, of aformula: ##STR6## (2)3-(4-Methylbenzyl)-2,2,6,6-tetramethyl-4-piperidinol, Compound A2, of aformula: ##STR7## (3)3-(2-Methylbenzyl)-2,2,6,6-tetramethyl-4-piperidinol, Compound A3, of aformula: ##STR8## (4)3-(4-t-Butylbenzyl)-2,2,6,6-tetramethyl-4-piperidinol, Compound A4, of aformula: ##STR9## (5)3-(2-t-Butylbenzyl)-2,2,6,6-tetramethyl-4-piperidinol, Compound A5, of aformula: ##STR10## (6) 3-Benzyl-1,2,2,6,6-pentamethyl-4-piperidinol,Compound A6, of a formula: ##STR11## (7)3-(4-Methylbenzyl)-1,2,2,6,6-pentamethyl-4-piperidinol, Compound A7, ofa formula: ##STR12## (8)3-(2-Methylbenzyl)-1,2,2,6,6-pentamethyl-4-piperidinol, Compound A8, ofa formula: ##STR13## (9)3-(4-t-Butylbenzyl)-1,2,2,6,6-pentamethyl-4-piperidinol, Compound A9, ofa formula: ##STR14## (10)3-(2-t-Butylbenzyl)-1,2,2,6,6-pentamethyl-4-piperidinol, Compound A10,of a formula: ##STR15## (11)3-Furfuryl-2,2,6,6-tetramethyl-4-piperidinol, Compound A11, of aformula: ##STR16## (12) 3-Furfuryl-1,2,2,6,6-pentamethyl-4-piperidinol,Compound A12, of a formula: ##STR17## (13)3-Benzylidene-2,2,6,6-tetramethyl-4-piperidinol, Compound A13, of aformula: ##STR18## (14)3-Benzylidene-1,2,2,6,6-pentamethyl-4-piperidinol, Compound A14, of aformula: ##STR19## (15)3-Furfurylidene-2,2,6,6-tetramethyl-4-piperidinol, Compound A15, of aformula: ##STR20## (16)3-Furfurylidene-1,2,2,6,6-pentamethyl-4-piperidinol, Compound A16, of aformula: ##STR21## (17)1-Benzyl-3-benzylidene-2,2,6,6-tetramethyl-4-piperidinol, Compound A17,of a formula: ##STR22## (18)1-Acetyl-3-benzyl-2,2,6,6-tetramethyl-4-piperidinol, Compound A18, of aformula: ##STR23## (19)1-Benzoyl-3-benzyl-2,2,6,6-tetramethyl-4-piperidinol, Compound A19, of aformula: ##STR24##

2) The piperidinols of the second sub-class

The piperidinols of the second sub-class correspond to hydrogenationproducts of the piperidinols of the first sub-class.

More particularly, the group ═CH--R⁵ or the group --CH₂ --R⁵ as R⁴ whenR³ is H in the first sub-class is --CH₂ --R⁵ wherein R⁵ is unsubstitutedor C₁ -C₄ alkyl-substituted cyclohexyl group or a tetrahydrofuryl group.R¹, R² and R^(2') have the same meaning in the first sub-class.

The piperidinols of the second sub-class are those where R¹ -R⁵ are asfollows.

R¹ is either one of a hydrogen atom, an alkyl group of 1 to 4 carbonatoms such as methyl and n-butyl, an acyl group of 2 to 7 carbon atomssuch as acetyl and benzyl, or an arylalkyl of 7 to 10 carbon atoms suchas benzyl and 1-phenylethyl. R¹ is preferably a hydrogen atom or amethyl group from the viewpoint of production of the compounds, althoughall of the R¹ s referred to above may provide the compounds withimproved photostabilizing capability.

R² is either one of a hydrogen atom, or an alkyl group of 1 to 4 carbonatoms such as a methyl group and a n-butyl group. R² is preferably ahydrogen atom or a methyl group, a hydrogen atom being more preferable;

R³ and R⁴ are such that R³ indicates a hydrogen atom and R⁴ indicates agroup --CH₂ --R⁵ where R⁵ is unsubstituted or a C₁ -C₄ alkyl-substitutedcyclohexyl group or a tetrahydrofuryl group.

Examples of R⁵ here include a cyclohexyl group, 2-methylcyclohexylgroup, 4-methylcyclohexyl group, 2-ethylcyclohexyl group,4-ethylcyclohexyl group, 2-isopropylcyclohexyl group,4-isopropylcyclohexyl group, 2-t-butylcyclohexyl group,4-t-butylcyclohexyl group and tetrahydrofuryl group, wherein acyclohexyl group is preferable.

Examples of the piperidinols of the second sub-class include:

(1) 3-Cyclohexylmethyl-2,2,6,6-tetramethyl-4-piperidinol, Compound B1,of a formula: ##STR25## (2)3-(4-Methylcyclohexylmethyl)-2,2,6,6-tetramethyl-4-piperidinol, CompoundB2, of a formula: ##STR26## (3)3-(2-Methylcyclohexylmethyl)-2,2,6,6-tetramethyl-4-piperidinol, CompoundB3, of a formula: ##STR27## (4)3-(4-t-Butylcyclohexylmethyl)-2,2,6,6-tetramethyl-4-piperidinol,Compound B4, of a formula: ##STR28## (5)3-(2-t-Butylcyclohexylmethyl)-2,2,6,6-tetramethyl-4-piperidinol,Compound B5, of a formula: ##STR29## (6)3-Tetrahydrofurfuryl-2,2,6,6-tetramethyl-4-piperidinol, Compound B6, ofa formula: ##STR30## (7)3-Cyclohexylmethyl-1,2,2,6,6-pentamethyl-4-piperidinol, Compound B7, ofa formula: ##STR31## (8)3-(4-Methylcyclohexylmethyl)-1,2,2,6,6-pentamethyl-4-piperidinol,Compound B8, of a formula: ##STR32## (9)3-(2-Methylcyclohexylmethyl)-1,2,2,6,6-pentamethyl-4-piperidinol,Compound B9, of a formula: ##STR33## (10)3-(4-t-Butylcyclohexylmethyl)-1,2,2,6,6-pentamethyl-4-piperidinol,Compound B10, of a formula: ##STR34## (11)3-(2-t-Butylcyclohexylmethyl)-1,2,2,6,6-pentamethyl-4-piperidinol,Compound B11, of a formula: ##STR35## (12)3-Tetrahydrofurfuryl-1,2,2,6,6-pentamethyl-4-piperidinol, Compound B12,of a formula: ##STR36## (13)1-Benzyl-3-cyclohexylmethyl-2,2,6,6-tetramethyl-4-piperidinol, CompoundB13, of a formula: ##STR37## (14)1-Acetyl-3-cyclohexylmethyl-2,2,6,6-tetramethyl-4-piperidinol, CompoundB14, of a formula: ##STR38## (15)1-Benzoyl-3-cyclohexylmethyl-2,2,6,6-tetramethyl-4-piperidinol, CompoundB15, of a formula: ##STR39##

Piperidinyl Esters

The compounds of this class are those of the formula [I] where R⁰ isR--CO)_(n).

The compounds of formula [I] of this class are those where R-R⁵ are asfollows:

R indicates a saturated alkyl group, a saturated alkylene group orarylene group of 1 to 20 carbon atoms which can have 1 to 4 carboxylicgroup attached thereto.

The terms "alkyl group" and "alkylene group" herein include a cycloalkylgroup and a cycloalkylene group, respectively, and "cycloalkylene group"includes those having a linear alkylene group such as ##STR40## The term"arylene group" includes those having a linear alkylene group such as##STR41##

Preferred R is an alkyl group and an alkylene group, and examples of thepreferred R, when indicated as R--COOH)_(n), include: acetic acid,propionic acid, butyric acid, cyclopentane carboxylic acid, cyclohexanecarboxylic acid, caprylic acid, 2-ethylhexanoic acid, lauric acid,stearic acid, bicyclo[2,2,1]heptane-2-carboxylic acid, malonic acid,succinic acid, maleic acid, glutaric acid, adipic acid,1,2-cyclopentanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid,1,4-cyclohexanedicarboxylic acid, sebacic acid, 1,10-decanedicarboxylicacid,bicyclo[2,2,1]heptane-2-carboxylic acid, 1,2,3-propanetricarboxylicacid, 1,2,3-butanetricarboxylic acid, 1,3,5-pentanetricarboxylic acid,1,2,4-cyclohexanetricarboxylic acid, 1,3,5-cyclohexanetricarboxylicacid, 1,1,2,3-ethanetetracarboxylic acid,1,1,2,3-propanetet-racarboxylic acid, 1,2,3,4-butanetetracarboxylicacid, 1,2,4,5-cyclohexanetetracarboxylic acid, andbicyclo[2,2,2]octane-2,3,5,6-tetracarboxylic acid.

R¹ is preferably a hydrogen atom or an alkyl group of 1 to 4 carbonatoms, and a hydrogen atom or a methyl group is more preferable.

R² and R^(2') are preferably a hydrogen atom or a methyl group, and ahydrogen atom is more preferable from the viewpoint of production of thecompounds, although they all provide the compounds with improvedphotostabilizing capability.

R³ and R⁴ are preferably such that R³ and R⁴ in combination indicate (i)a benzylidene group or a C₁ -C₄ alkyl-substituted benzylidene group or(ii) a cyclohexylmethylidene group or a C₁ -C₄ alkyl-substitutedcyclohexylmethylidene, or (iii) R³ is a hydrogen atom and R⁴ is a benzylgroup or a C₁ -C₄ alkyl-substituted benzyl or a cyclohexylmethyl groupor a C₁ -C₄ alkyl-substituted cyclohexylmethyl group.

In view of solubility in various organic material, especiallypolyolefins, and resistance to hydrolysis, of the compounds of thisclass, R³ and R⁴ are more preferably such that (a) R³ and R⁴ incombination are a benzylidene group or a C₁ -C₄ alkyl-substitutedbenzylidene, or a cyclohexylmethylidene or a C₁ -C₄ alkyl-substitutedcyclohexylmethylidene, or (b) R³ is a hydrogenatom and R⁴ is a benzylgroup or a C₁ -C₄ alkyl-substituted benzyl group, or a cyclohexylmethylor a C₁ -C₄ alkyl-substituted cyclohexylmethyl group, and still morepreferably R³ is a hydrogen atom and R⁴ is a benzyl group or a C₁ -C₄alkyl-substituted benzyl group, or a cyclohexylmethyl group or a C₁ -C₄substituted cyclohexylmethyl group.

n is an integer of 1 to 4, preferably 1 or 2.

Examples of the piperidinyl esters of this class include:

(1) 3-Benzyl-2,2,6,6-tetramethylpiperidin-4-yl cyclohexanecarboxylate,Compound C1, of a formula: ##STR42## (2)3-Cyclohexylmethyl-2,2,6,6-tetramethyl-2,2,6,6-tetramethylpiperidin-4-ylcyclohexanecarboxylate, Compound C2, of a formula: ##STR43## (3)3-Benzylidene-2,2,6,6-tetramethylpiperidin-4-yl stearate, Compound C3,of a formula: ##STR44## (4) 3-Benzyl-2,2,6,6-tetramethylpiperidin-4-ylstearate, Compound C4, of a formula: ##STR45## (5)3-Cyclohexylmethyl-2,2,6,6-tetramethylpiperidin-4-yl stearate, CompoundC5, of a formula: ##STR46## (6)3-Cyclohexylmethyl-1,2,2,6,6-pentamethylpiperidin-4 -yl stearate,Compound C6, of a formula: ##STR47## (7)Bis(3-benzyl-2,2,6,6-tetramethylpiperidin-4-yl) adipate, Compound C7, ofa formula: ##STR48## (8)Bis(3-cyclohexylmethyl-2,2,6,6-tetramethylpiperidin-4-yl) adipate,Compound C8, of a formula: ##STR49## (9)Bis(3-benzylidene-2,2,6,6-tetramethylpiperidin-4-yl) dicarboxylate,Compound C9, of a formula: ##STR50## (10)Bis(3-benzyl-2,2,6,6-tetramethylpiperidin-4-yl)1,4-cyclohexanedicarboxylate, Compound C10, of a formula: ##STR51## (11)Bis(3-cyclohexylmethyl-2,2,6,6-tetramethylpiperidin-4-yl)1,4-cyclohexanedicarboxylate, Compound C11, of a formula: ##STR52## (12)Bis(3-cyclohexylmethyl-1,2,2,6,6-pentamethylpiperidin-4-yl)1,4-cyclohexanedicarboxylate, Compound C12, of a formula: ##STR53## (13)Bis(3-benzylidene-2,2,6,6-tetramethylpiperidin-4 -yl) sebacate, CompoundC13, of a formula: ##STR54## (14)Bis(3-benzyl-2,2,6,6-tetramethylpiperidin-4-yl) sebacate, Compound C14,of a formula: ##STR55## (15)Bis(3-cyclohexylmethyl-2,2,6,6-tetramethylpiperidin-4-yl) sebacate,Compound C15, of a formula: ##STR56## (16)Bis(3-cyclohexylmethyl-1,2,2,6,6-pentamethylpiperidin-4-yl) sebacate,Compound C16, of a formula: ##STR57## (17)Tris(3-benzyl-2,2,6,6-tetramethylpiperidin-4-yl)1,2,3-propanetricarboxylate, Compound C17, of a formula: ##STR58## (18)Tris(3-cyclohexylmethyl-2,2,6,6-tetramethylpiperidin-4-yl)1,2,3-propanetricarboxylate, Compound C18, of a formula: ##STR59## (19)Tris(3-benzylidene-2,2,6,6-tetramethylpiperidin-4-yl)1,2,4-cyclohexanetricarboxylate, Compound C19, of a formula: ##STR60##(20) Tris(3-benzyl-2,2,6,6-tetramethylpiperidin-4-yl)1,2,4-cyclohexanetricarboxylate, Compound C20, of a formula: ##STR61##(21) Tris(3-cyclohexylmethyl-2,2,6,6-tetramethylpiperidin-4-yl)1,2,4-cyclohexanetricarboxylate, Compound C21, of a formula: ##STR62##(22) Tris(3-cyclohexylmethyl-1,2,2,6,6-pentamethylpiperidin-4-yl)1,2,4-cyclohexanetricarboxylate, Compound C22, of a formula: ##STR63##(23) Tetrakis(3-benzylidene-2,2,6,6-tetramethylpiperidin-4-yl)1,2,3,4-butanetetracarboxylate, Compound C23, of a formula: ##STR64##(24) Tetrakis(3-benzyl-2,2,6,6-tetramethylpiperidin-4-yl)1,2,3,4-butanetetracarboxylate, Compound C24, of a formula: ##STR65##(25) Tetrakis(3-cyclohexylmethyl-1,2,2,6,6-pentamethylpiperidin-4-yl)1,2,3,4-butanetetracarboxylate, Compound C25, of a formula: ##STR66##(26) Tetrakis(3-cyclohexylmethyl-1,2,2,6,6-pentamethylpiperidin-4-yl)1,2,3,4-butanetetracarboxylate, Compound C26, of a formula: ##STR67##

Production of the Compounds

The piperidine derivatives in accordance with the present invention areproduced by any suitable methods in terms of forming of bonds or groupsor substituents in the compounds.

An example of one of suitable methods is to hydrogenate a piperidinoneof a formula [II] thereby to produce the compounds of the formula [I]where R⁰ is H as set forth in the reaction scheme A given hereinbelow,which will then be esterified into the compound of the formula [I] whereR⁰ is R--CO)_(n).

(A) Production of the piperidinols ##STR68##

(1) Starting materials

The compound of a formula [II] used as a starting material in thereaction scheme A given above may be prepared by any suitable methodsuch as that shown in Japanese Patent Publication Nos. 42987/1979 and30307/1983.

More particularly, 3-benzylidene-2,2,6,6-tetramethylpiperidinone, forexample, is prepared from 2,2,6,6-tetramethyl-4-piperidinone andbenzaldehyde.

The compounds of the formula [II] obtained in accordance with the methodof the Japanese Patent Publications may be in the form of a mixture ofthe Z-isomer and the E-isomer.

The compound [II] in the scheme A is in the form of a mixture of theisomers, or alternatively either of the isomers separated from themixture. Use of the mixture of the isomers may usually be preferred.

The hydrogenation may follow any of the convenient or conventionalmethods including the following methods.

(2) Catalytic hydrogenation

Preferable hydrogenation is catalytic hydrogenation, whereby thecompound [II] which can be a mixture of Z- and E-isomers as shown aboveis hydrogenated in a vessel with hydrogen gas introduced into the vesselin the presence of a hydrogenation catalyst and an optional solvent ordispersant, and the hydrogenation product of the compound [II], namelythe compound [I] of the present invention or the compound [I'] which isalso a compound of the present invention falling in the scope of theformula [I], is separated from the catalyst and the solvent/dispersantused.

The catalytic hydrogenation may be carried out in a batchwise way, in aone-through method or in a recycling method.

The hydrogenation conditions comprise a reaction temperature may be -80°C. to 300° C., preferably 0° C. to 150° C., and a hydrogen pressure of0.1 to 200 atms, preferably 1 to 150 atms when R³ and R⁴ containunsaturation or a temperature of 0° C. to 300° C., preferably 50° C. to200° C. and a hydrogen pressure of 1 to 300 atms, preferably 10 to 150atms when R³ and R⁴ do not contain unsaturation.

Suitable solvent/dispersants may be selected depending on the type ofreactants used or stability under reducing conditions, and are alcohols,esters or hydrocarbons, among which ethanol, isopropanol,tetrahydrofuran, dioxane and mineral spirit are preferable. These areused singly or in admixture.

The hydrogenation reaction is carried out in the presence of ahydrogenation catalyst Any hydrogenation catalysts which are known tohave activity for hydrogenation can be used, including metals of theGroup VIII of the Periodic Table such as palladium, platinum, ruthenium,rhodium, irridium, cobalt and nickel in the form of powder, a complex oroxide powder, or in the form supported on a support/carrier such asactivated carbon, silica or alumina in an amount of 0.5 to 20% byweight.

Preferable among these are ruthenium on activated carbon, ruthenium onalumina, rhodium on activated carbon, rhodium on alumina and Raneynickel.

The amount of a catalyst is, usually, 0.01 to 10% by weight, preferably0.05 to 5% by weight, of the compound [II].

(3) Chemical reduction

The piperidine derivatives in accordance with the present invention canalternatively be produced by a chemical reduction of the compound [II]with a reducing agent.

Examples of the reducing agent include metal hydrides such as sodiumborohydride, lithium aluminum hydride, boron hydrides such as diborane,hydrazine and ammonia, which are used usually in an amount capable ofsupplying hydrogen in an amount of 1 to 1.2 times the stoichiometricamount of hydrogen required.

The reaction is carried out usually in a solvent/dispersant whichdissolves the reactants and the reducing agents and is stable under thereducing conditions, such as alcohols, ethers and hydrocarbons.

The reaction is carried out usually at a temperature of -80° C. to 150°C., preferably 0° C. to 100° C.

It is possible to conduct the reaction in the presence of an additive inorder to improve reaction velocity and/or selectivity, includingalkaline or alkaline earth metal hydroxides such as LiOH, NaOH and KOH,stannous or stannic compounds such as SnCl₂, SnCl₄ and SnO₂, and H₂ O,in an amount of 0.1 to 5% by weight.

The catalytic hydrogenation (2) and the chemical reduction (3) can becombined to produce the piperidine derivatives in accordance with thepresent invention of the formula [I] where R⁰ is H.

(B) Production of piperidinyl esters

The piperidinyl esters in accordance with the present invention areproduced by any suitable methods in terms of forming of bonds or groupsor substituents in the compound.

An example of one of suitable methods is to esterify a compound of theformula [I] where R⁰ is H with a carboxylic acid of R--COOH)_(n) whichmay be in the form of a carboxylic acid, an ester with a lower alkanol,an acid anhydride or an acid halide.

Preferable method comprises ester interchange where the carboxylic acidis used in the form of an ester with a lower alkanol such as methanol asshown in the scheme B given below. ##STR69##

The ester interchange reaction is usually carried out in the presence ofa basic catalyst such as lithiumamide, or sodium methoxide and anorganic solvent such as hexane, heptane, toluene or dioxane. Thereaction temperature may be 0° C. to a reflux temperature, preferably50° C. to 150° C.

Utility/Use of the Compounds

The compounds of the formula [I] in accordance with the presentinvention are useful as compounds having a hindered amine structure instabilization, especially photostabilization, of various organicmaterials as such or as derivatives thereof such that the hydroxylgroup, when R⁰ is H, is utilized is reacted with a mono- or poly (suchas di- or tri-) basic carboxylic acid into esters, the compounds of theformula [I] where R⁰ is R--CO)_(n) being particular examples of suchesters, with a mono- or poly (such as di- or tri-) isocyanate intomethanes

The compounds of the formula [I] where R¹ is H and R⁰ is H areaminoalcohol compounds and can thus be converted, upon reaction with adicarboxylic acid, into poly (ester/amide)s which can also be used as astabilizer and the like.

More particularly, the piperidinols of the formula [I] where R⁰ is H inaccordance with the present invention have a secondary or a tertiaryamino group as well as a secondary alcoholic hydroxyl group, and arethus equipped with reactivities inherent in these functional groups. Forinstance, the compounds may thus be converted into esters or amides, andparticularly, when the carboxylic acid is a polycarboxylic acid, intobis esters or polyesteramides of a high molecular weight when thepolycarboxylic acid is a dicarboxylic acid. Examples of the dicarboxylicacid include those of 2 to 16, preferably 2 to 10 carbon atoms includingaliphatic acids, alicyclic such as cyclohexanecarboxylic acid andaromatic carboxylic acid such as terephthalic acid. It goes withoutsaying that the esterification can be conducted so that one or both ofthe reactants is in its functional derivative, for instance thedicarboxylic acid is in the form of a diester with a lower alkanol toform an ester through ester interchange.

Organic materials to be stabilized against light by incorporationthereinto of the piperidine derivatives of the formula [I] in accordancewith the present invention include a lot of materials. Representativegroup of such organic materials is high polymeric materials such as, forexample, poly α-olefins such as low-density polyethylenes, mediumdensity polyethylenes, linear low-density polyethylenes, polypropylenes,polybutene-1, α-olefin copolymers such as ethylene-propylene random orblock copolymers, ethylene-butene-1 copolymers, and copolymers of anα-olefin with a vinyl monomer such as polypropylenes modified withmaleic anhydride through grafting, which are as such or in admixturethereof. Most typical polymeric material is polypropylene.

Other polymeric materials other than those referred to above can also bephotostabilized by the piperidine derivatives in accordance with thepresent invention, which include polyvinyl chlorides, polymethacrylicresins, styrene-based resins, e.g. polystyrenes, high impactpolystyrenes, ABS resins and AES resins, polyester resins such aspolyethylene terephthalate and polybutylene terephthalate, polyamides,polycarbonates, polyacetals, polyethylene oxides, polyphenylene ethers,polysulfones, polyurethanes and unsaturated polyester resins.

Naturally occurring organic materials are other examples of organicmaterials stabilized against photodegradation by incorporation thereintoof the piperidine derivatives in accordance with the present invention,which include naturally occurring polymeric materials, e.g. celluloses,rubbers, proteins or their derivatives such as cellulose acetates,mineral oils, animal and vegetable fat and oil, and waxes.

The piperidine derivatives in accordance with the present invention areused solely as a stabilizer against photodegradation of organicmaterials, but they can be used in combination with anotherphotostabilizer upon necessity.

The following examples are given only for describing the presentinvention in more detail.

EXAMPLE A1 3-Benzyl-2,2,6,6-tetramethyl-4-piperidinol, Compound A1

Into a 50 ml-flask equipped with a thermometer, a gas inlet, a coolingtube and a magnetic stirrer were introduced 2.0 g (8.2 mmol) of3-Z-benzylidene-2,2,6,6-tetramethyl-4-piperidinone and 25 ml of ethanol,and then nitrogen gas through the gas inlet under stirring. Upon theflask being filled with nitrogen, 0.10 g of a Pd-on-carbon catalystcontaining 10% of Pd, supplied by N.E. Chemcat K.K., Japan wasintroduced under nitrogen into the flask and the content in the flaskwas agitated. After ca. 2 minutes, hydrogen was introduced, andhydrogenation was carried out for 2 hours at room temperature underatmospheric pressure.

Introduction of hydrogen was then stopped, and nitrogen was introducedinto the flask through the gas inlet to drive the hydrogen off theflask, and the solution in the flask was then filtered to remove thecatalyst used.

The solution thus obtained was introduced a 100 ml-flask equipped with athermometer, a cooling tube and a magnetic stirrer, and 0.75 g (20 mmol)of NaBH₄ was gradually introduced under agitation of the solution. Afterone hour, 10% aq. HCl was introduced so that the pH of the solutionbecame 6, and an excess amount of NaBH₄ was removed. To the solution wasthen added 10% aq. NaOH so that the pH of the solution became 8 and thesolution was agitated thoroughly. The solution was then subjected toreduced pressure to distill the ethanol off.

The white solid matter precipitated was extracted with 100 ml ofdiethylether, and the extract obtained was washed three times with 20 mlof water. To the solution obtained was added 10 g of magnesium sulfate,and after 2 hours of standing, the solution was filtered andconcentrated to give 1.85 g of a white solid product. The white solidproduct obtained gave, upon recrystallization from its acetonitrilesolution, 1.7 g (yield: 84%) of the title compound as white crystals.

The physical data of this compound is as follows.

(1) Melting point: 140.0° C.

(2) Molecular weight: M⁺ =247 (m/e)

(3) ¹ H-NMR (CDCl₃) δ(ppm) (FIG. A1): 0.75-0.95 (bs, 1H), 1.00-1.45 (m,13H), 1.48-1.75 (m, 2H), 2.60-2.90 (m, 2H), 3.80-4.10 (m, 1H), 7.05-7.35(m, 5H)

(4) ¹³ C-NMR (CDCl₃) δ(ppm) (FIG. A2): 27.7, 31.6, 32.3, 32.9, 34.1,44.4, 49.4, 50.8, 53.2, 66.3, 125.6, 128.3, 129.0, 142.0

EXAMPLE A2 3-Z-Benzylidene-2,2,6,6-tetramethyl-4-piperidinol, CompoundA13

Into a 200 ml-flask equipped with a thermometer, a cooling tube and amagnetic stirrer were introduced 10.0 g (41 mmol) of3-Z-benzylidene-2,2,6,6-tetramethyl-4-piperidinone and 100 ml ofmethanol, and the content was agitated into a homogeneous solution.After the solution was cooled to 0° to 5° C. in an ice bath, 3.8 g (100mmol) of NaBH₄ was gradually introduced into the solution so that thetemperature of the solution was maintained no higher than 10° C. and thereaction was continued for 3 hours. Then, 10% aqueous HCl was added tothe solution so that the pH became 6, and the excess NaBH₄ was removed.To the solution was added 10% aqueous NaOH so that the pH became 8, andthe solution, after thorough agitation, was subjected to reducedpressure to distill the methanol off.

The white solid matter precipitated was extracted with 200 ml ofdiethylether, and the extract obtained was washed three times with 30 mlof water. To the solution obtained was added 10 g of magnesium sulfate,and after 2 hours of standing, the solution was filtered andconcentrated to give 9.5 g of a white solid product. The white solidproduct obtained gave, upon recrystallization from its acetonitrilesolution, 8.7 g (yield: 86%) of the title compound as white crystals.

The physical data of this compound is as follows.

(1) Melting point: 136.9° C.

(2) Molecular weight: M⁺ =245 (m/e)

(3) ¹ H-NMR (CDCl₃) δ(ppm): 0.91-1.68 (m, 14H), 1.93-2.09 (m, 1H),2.99-3.20 (m, 1H), 4.62-4.82 (m, 1H), 6.48-6.52 (s, 1H), 7.10-7.42 (m,5H)

(4) ¹³ C-NMR (CDCl₃) δ(ppm): 33.1, 33.4, 35.3, 35.6, 42.4, 49.0, 54.6,66.3, 124.9, 126.7, 128.2, 128.8, 137.0, 147.9

EXAMPLE A3 3-Benzyl-1,2,2,6,6-pentamethyl-4-piperidinol, Compound A6

Into a 100 ml-flask equipped with a thermometer, a cooling tube, adropping funnel and a magnetic stirrer were added 3.7 g of3-benzyl-2,2,6,6-tetramethyl-4-piperidinol prepared in Example A1 above,30 ml of dioxane and 0.78 g of fumic acid, and the content in the flaskwas heated to 80° C. When the temperature of the content was at aconstant level, 2.44 g of 37% aqueous formaldehyde in which 10 ml ofdioxane had been dissolved was introduced gradually through the droppingfunnel, and the content of the flask was heated at the same temperatureunder agitation for 8 hours. The temperature was then lowered to roomtemperature, 10% aqueous NaOH was added so that the pH became to 7, andthe solution was subjected to extraction with 150 ml of diethylether.The extract obtained was washed three times with 30 ml of water, 10 g ofmagnesium sulfate and the solution was kept standing for 2 hours, andthe solution was filtered and concentrated to give 3.3 g (yield: 83%) ofthe title compound as a white solid product.

The physical data of this compound is as follows.

(1) Melting point: 84.3° C.

(2) Molecular weight: M⁺ =261 (m/e)

(3) ¹ H-NMR (CDCl₃) δ(ppm): 0.89-2.02 (m, 16H), 2.19-2.45 (s, 3H),2.73-3.07 (d, 2H), 3.88-4.14 (m, 1H), 7.02-7.61 (m, 5H)

(4) ¹³ C-NMR (CDCl₃) δ(ppm): 24.9, 25.8, 26.3, 28.2, 29.5, 31.6, 45.8,52.4, 54.1, 58.2, 66.0, 125.4 128.2, 129.1, 143.2

EXAMPLE A3 Bis(3-benzyl-2,2,6,6-tetramethyl-4-piperidyl) sebacate,Compound A1 ' (C14)

To a 300 ml-flask equipped with a thermometer, a Dien-Stark cooling tubeand a magnetic stirrer were introduced 5.93 g (24 mmol) of 3benzyl-2,2,6,6-tetramethyl-4-piperidinol, Compound A1, prepared inExample A1, 2.30 g (10 mmol) of dimethyl sebacate, 0.1 g of NaOCH₃ as acatalyst and 200 ml of heptane, and the content of the flask was heatedat a reflux temperature for ca. 8 hours to carry out the reaction.

The content of the flask was then cooled to room temperature, 200 ml ofdiethylether was added thereto, and the mixture was washed with 50 ml ofwater three times.

The organic layer obtained was dried by 10 g of magnesium sulfate addedthereto for ca. 3 hours. The magnesium sulfate was then filtered off,and the solvent was distilled off in vacuo to give 8.04 g of a white waxproduct. The white wax product obtained was purified by alumina columnchromatography, the solvent being chloroform, to give 5.20 g (yield:79.0%) of the title compound as a white wax product.

The physical properties of the product are as follows.

(1) Molecular weight: M⁺ =660 (m/e)

(2) ¹ H-NMR (CDCl₃) δ(ppm): 0.90-1.48 (m, 36H), 1.52-1.78 (m, 6H),1.80-1.96 (dd, 2H), 2.18-2.46 (t, 4H), 2.48-2.89 (m, 4H), 4.92-5.09 (m,2H), 7.06-7.43 (m, 10H)

(3) ¹³ C-NMR (CDCl₃) δ(ppm): 25.0, 26.8, 29.1, 29.2, 30.5, 32.8, 33.1,34.4, 34.9, 40.6, 49.3, 49.7, 49.8, 53.1, 69.8, 126.0, 128.4, 128.9,140.8, 173.0

EVALUATION A1

To 100 parts by weight of powder of polypropylene having an intrinsicviscosity of 1.9 determined at 135° C. in tetralin and a content of theisotactic fraction of 98% were added 0.2 parts by weight of the sampleprepared in Examples A1, A2 and A3, respectively, and 0.1 part by weightof tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxymethyl]methane, and the mixtures were thoroughly mixed by a mixer, and themixture was kneaded and extruded from an extruder of a cylindertemperature of 260° C. and an extruder diameter of 20 mm into pellets.

The pellets were press-molded at 230° C. into a sheet of 0.5 mm thick toform a test piece, test pieces 1, 2 and 3.

Other pieces were prepared from resin compositions which were the sameas those used in forming test pieces 1, 2 and 3 except that, in place ofthe piperidine derivatives,3-Z-benzylidene-2,2,6,6-tetramethyl-4-piperidinone, comparative compound(i), prepared in accordance with the method disclosed in Japanese PatentPublication Nos. 42987/1979 and 30307/1983 and LS770 which was acommercially available hindered amine photostabilizer produced andsupplied by Sankyo Co., Ltd., Japan, were respectively used.

These test pieces were subjected to a photostabilization test by axenone weather-O-meter, Model 65/XW-WR, manufactured by Atlas Corp.under irradiation with light at the black panel temperature of 80° C.until the test pieces became deteriorated, and the time required untilthe deterioration was measured and recorded in Table A1 given below.

                  TABLE A1                                                        ______________________________________                                                               Time until                                             No.       Additive     deterioration, Hr.                                     ______________________________________                                        1a        --           100                                                    2a        Comp. compd. (i)                                                                           110                                                    3a        Compound A1  430                                                    4a        Compound A13 240                                                    5a        Compound A1' 520                                                    6a        LS770        320                                                    ______________________________________                                    

As is evident from the results set forth in Table A1, the piperidinederivatives in accordance with the present invention are improvedphotostabilization, namely elongation of the time until thedeterioration, irrespective of whether they are piperidinols or asebacate thereof in Nos. 3a, 4a and 5a than the reference compounds inNos. 1a, 2a and 6a.

EVALUATION A2

The pellets obtained in Evaluation A1 were subjected to determination ofthe yellowness index, YI. The yellowness index was determined by ColorTester manufactured by Suga Testing Machine Co., Ltd., Japan.

The results obtained are set forth in Table A2.

                  TABLE A2                                                        ______________________________________                                        Sample tested    YI                                                           ______________________________________                                        Compound A1      8.9                                                          Compound A13     7.1                                                          Comp. Compd. (i) 17.9                                                         LS770            9.1                                                          Compound A1'     11.8                                                         ______________________________________                                    

EVALUATION A3

The test pieces containing Compound A1' and LS770 were subjected toweathering test by a weather-O-meter for 300 hours.

No breeding was observed for the test piece containing Compound A1', butbreeding was observed for the test piece containing LS770 in that thesheet had white powdery material adhering on its surface, which waswiped off to show that it was a breed.

EXAMPLE B1 3-Cyclohexylmethyl-2,2,6,6-tetramethyl-4-piperidinol,Compound B1

Into a pressure-resistant vessel of a volume of 260 ml equipped with aninduction stirrer, a gas inlet and a thermocouple were introduced 20.0 g(82.2 mmol) of 3-Z-benzylidene-2,2,6,6-tetramethyl-4-piperidinone and150 ml of ethanol. The- vessel was purged with nitrogen under stirring,and 1.0 g of 5% Rh-on-carbon catalyst (N.E. Chemcat) was introduced andthe vessel was sealed 2 minutes after, hydrogen gas under 70 atm wasintroduced through the gas inlet and the reaction was carried out at 65°C. for 5 hours.

The vessel was then cooled down to room temperature, and nitrogen wasintroduced through the gas inlet into the vessel to expel the hydrogenin the vessel, whereupon the vessel was opened and the solution obtainedwas filtered to remove catalyst.

The solution obtained was charged into a 500 ml-flask equipped with athermometer, a cooling tube and a magnetic stirrer, and 3.0 g (80 mmol)of NaBH₄ was gradually added under stirring 5 hours after, a 10% aqueousHCl was added to the solution so that the pH became 6, and an excessamount of NaBH₄ was removed. A 10% aqueous NaOH was then added to thesolution so that the pH became 8, and after ample stirring, the solutionwas subjected to a reduced pressure to distill off the ethanol. Thewhite solid material precipitated was extracted with 1000 ml of diethylether, and the extract was washed with 100 ml of water 5 times. 20 g ofmagnesium sulfate was added to the solution obtained, and after standingfor ca. 2 hours, the solution was filtered and concentrated to give 19.8g of a white solid, which was recrystallized from hexane to give 17.5 g(yield: 84%) of the title compound as white crystals.

The physical properties of the product are as follows.

(1) Melting point: 144.8° C.

(2) Molecular weight: M⁺ =253 (m/e)

(3) ¹ H-NMR (CDCl₃) δ(ppm) (FIG. B1): 0.47-1.83 (m, 29H), 4.09-4.28 (m,1H)

(4) ¹³ C-NMR (CDCl₃) δ(ppm) (FIG. B2): 26.7, 26.9, 28.6, 32.3, 32.9,33.0, 33.2, 33.7, 34.5, 36.7, 43.7, 45.4, 50.1, 53.7, 67.6

EXAMPLE B2 3-Cyclohexylmethyl-1,2,2,6,6-pentamethyl-4-piperidinol,Compound B7

Into a 100 ml-flask equipped with a thermometer, a cooling tube, adropping funnel and a magnetic stirrer were introduced 3.8 g (15 mmol)of 3-cyclohexylmethyl-2,2,6,6-tetramethyl-4-piperidinol prepared inExample B1, 70 ml of dioxane and 0.78 g (17 mmol) of formic acid, andthe content of the flask was heated to 80° C. When the temperature ofthe content of the flask was constant, 2.44 g (30 mmol) of 37% aqueousformaldehyde dissolved in 20 ml of dioxane was added gradually throughthe dropping funnel, followed by heating at the temperature for 10hours. The content of the flask was cooled to room temperature, and 5%aqueous NaOH was added so that the pH became 8, followed by extractionwith 200 ml of diethylether. The extract obtained was washed with 30 mlof water 3 times, 10 g of magnesium sulfate was added and, after it waskept standing for ca. 2 hours, the solution was filtered andconcentrated to give 3.95 g (yield: 98%) of the title compound as awhite solid product.

The physical properties of the product obtained are as follows.

(1) Melting point: 95.1° C.

(2) Molecular weight: M⁺ =267 (m/e)

(3) ¹ H-NMR (CDCl₃) δ(ppm): 0.74-1.86 (m, 28H), 2.24 (s, 3H), 3.94-4.18(m, 1H)

(4) ¹³ C-NMR (CDCl₃) δ(ppm): 24.6, 25.8, 26.1, 26.8, 27.0, 28.5, 30.6,33.2, 33.9, 34.3, 37.7, 45.7, 47.6, 54.5, 58.4, 67.0, 67.4

EXAMPLE B3 Bis(3-cyclohexylmethyl-2,2,6,6-tetramethylpiperidin-4-yl)sebacate, Compound B1' (C15)

Into a 200 ml-flask equipped with a thermometer, a Dien Stark coolingtube and a magnetic stirrer were introduced 4.05 g (16 mmol) of3-cyclohexylmethyl-2,2,6,6-tetramethyl-4-piperidinol, 1.61 g (7 mmol) ofdimethyl sebacate, 0.1 g of LiNH₂ catalyst and 120 ml of heptane, andthe reaction was carried out at a reflux temperature for ca. 8 hours.

The content of the flask was then cooled to room temperature, 200 ml ofdiethylether was added, and the solution was washed with 50 ml of water3 times. The organic layer was then dried by 10 g of magnesium sulfateadded thereto for ca. 3 hours. The solution was filtered to remove themagnesium sulfate, and subjected to a reduced pressure to distill thesolvent used to give 5.34 g of a colorless transparent liquid product,which was purified by alumina chromatography, the solvent beingchloroform, to give 4.34 g (yield: 92.1%) of the title compound as acolorless transparent liquid product.

The physical properties of the product obtained are as follows.

(1) Molecular weight: M⁺ =672 (m/e)

(2) ¹ H-NMR (CDCl₃) δ(ppm): 0.70-1.80 (m, 70H), 2.29 (t, 4H), 5.20-5.30(m, 2H)

(3) ¹³ C-NMR (CDCl₃) δ(ppm): 25.0, 26.2, 26.4, 26.6, 27.1, 29.1, 31.2,32.6, 33.0, 33.6, 33.9, 34.4, 34.9, 35.5, 40.6, 43.7, 49.3, 53.0, 70.2,173.3

EVALUATION B1

To 100 parts by weight of powder of polypropylene having an intrinsicviscosity of 1.9 determined at 135° C. in tetralin and a content of theisotactic fraction of 98% were added 0.2 parts by weight of the sampleprepared in Examples B1 and 0.1 part by weight oftetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxymethyl]methane, and the mixture was thoroughly mixed by a mixer, and themixture was kneaded and extruded from an extruder of a cylindertemperature of 260° C. and an extruder diameter of 20 mm into pellets.

The pellets were press-molded at 230° C. into a sheet of 0.5 mm thick toform a test piece, test pieces 1 and 2.

Other pieces were prepared from resin compositions which were the sameas those used in forming test pieces 1 and 2 except that, in place ofthe piperidine derivatives,3-Z-benzylidene-2,2,6,6-tetramethyl-4-piperidinone, comparative compound(i), prepared in accordance with the method disclosed in Japanese PatentPublication Nos. 42987/1979 and 30307/1983 and LS770 which was acommercially available hindered amine photostabilizer produced andsupplied by Sankyo Co., Ltd., Japan, were respectively used.

These test pieces were subjected to a photostabilization test by axenone weather-o-meter, Model 65/XW-WR, manufactured by Atlas Corp.under irradiation with light at the black panel temperature of 80° C.until the test pieces became deteriorated, and the time required untilthe deterioration was measured and recorded in Table B1 given below.

                  TABLE B1                                                        ______________________________________                                                               Time until                                             No.       Additive     deterioration, Hr.                                     ______________________________________                                        1b        --           155                                                    2b        Comp. compd. (i)                                                                           170                                                    3b        Compound B1  470                                                    4b        Compound B1' 700                                                    5b        LS770        495                                                    ______________________________________                                    

As is evident from the results set forth in Table A1, the piperidinederivatives in accordance with the present invention are improvedphotostabilization, namely elongation of the time until thedeterioration, irrespective of whether they are piperidinols or asebacate thereof in Nos. 3b and 4b than the reference compounds in Nos.1b, 2b and 5b.

EVALUATION B2

The pellets obtained in Evaluation A1 were subjected to determination ofthe yellowness index, YI. The yellowness index was determined by ColorTester manufactured by Suga Testing Machine Co., Ltd., Japan.

The results obtained are set forth in Table B2.

                  TABLE B2                                                        ______________________________________                                        Sample tested    YI                                                           ______________________________________                                        Comp. Compd. (i) 10.4                                                         Compound B1      1.99                                                         Compound B1'     2.28                                                         LS770            2.06                                                         ______________________________________                                    

EVALUATION A3

The test pieces containing Compound B1' and LS770 were subjected toweathering test by a weather-O-meter for 300 hours.

No breeding was observed for the test piece containing Compound B1', butbreeding was observed for the test piece containing LS770 in that thesheet had white powdery material adhering on its surface, which waswiped off to show that it was a breed.

EXAMPLE C1 Bis(3-cyclohexylmethyl-2,2,6,6-tetramethyl-4-piperidinyl)sebacate, Compound C15 which is equal to Compound B1'

Into a 300 ml-flask equipped with a Dien Stark cooling tube wereintroduced 8.9 g (35 mmol) of3-cyclohexylmethyl-4-hydroxy-2,2,6,6-tetramethyl-4-piperidine, 3.5 g (15mmol) of dimethyl sebacate, 0.2 g (4 mmol) of LiNH₂ catalyst and 200 mlof heptane, and the reaction was carried out at a reflux temperature(100° C.) for 10 hours wherein methanol was distilled off azeotropicallywith n-heptane.

The content of the flask was then cooled to room temperature, 150 ml ofdiethylether was added, and the solution was washed with 50 ml of water2 times. The organic layer was then dried by anhydrous magnesium sulfateadded thereto. The solution was filtered to remove the magnesium sulfateand concentrated to give 10.8 g of a pale yellow transparent viscousliquid product, which was purified by alumina chromatography, thesolvent being chloroform, to give 9.3 g (yield: 92%) of the titlecompound as a colorless transparent viscous liquid product.

The physical properties of the product obtained are as follows.

(1) ¹ H-NMR (CDCl₃) δ(ppm) (FIG. C1): 0.70-1.80 (m, 70H), 2.29 (t, 4H),5.20-5.30 (m, 2H)

(2) ¹³ C-NMR (CDCl₃) δ(ppm) (FIG. C2): 25.0, 26.2, 26.4, 26.6, 27.1,29.1, 31.2, 32.6, 33.0, 33.6, 33.9, 34.4, 34.9, 35.5, 40.6, 43.7, 49.3,53.0, 70.2, 173.3

(3) IR (KBr) Wave number [cm⁻¹ ] (FIG. C3): 2920, 2850, 1732, 1448,1377, 1362, 1249, 1223, 1171, 1127, 1093, 1022, 979, 955, 720, 652, 459

EXAMPLE C2 Bis(3-cyclohexylmethyl-1,2,2,6,6-pentamethylpiperidin-4-yl)sebacate, Compound C16

The procedure set forth in Example C1 was followed except for the use of9.3 g (35 mmol) of3-cyclohexylmethyl-4-hydroxy-1,2,2,6,6-pentamethylpiperidine in place of3-cyclohexylmethyl-4-hydroxy-2,2,6,6-tetramethylpiperidine to produce11.1 g of pale yellow viscous liquid product, which was purified byalumina gel chromatography, the solvent being chloroform to give 9.8 g(yield: 93%) of the title compound as a colorless transparent viscousliquid product.

The physical properties of the product are as follows.

(1) ¹ H-NMR (CDCl₃) δ(ppm): 0.75-1.85 (m, 68H), 2.18-2.33 (m, 10H),5.17-5.25 (m, 2H)

(2) ¹³ C-NMR (CDCl₃) δ(ppm): 23.4, 24.9, 25.9, 26.4, 26.7, 27.5, 27.7,28.3, 29.2, 33.4, 33.5, 34.1, 34.9, 36.8, 41.9, 45.3, 53.9, 57.9, 69.9,173.4

EXAMPLE C3 Bis(3-cyclohexylmethyl-2,2,6,6-tetramethylpiperidin-4-yl)cyclohexanecarboxylate, Compound C11

The procedure set forth in Example C1 was followed except for the use of3.0 g (15 mmol) of 1,4-cyclohexanedicarboxylate in place of dimethylsebacate to produce 9.5 g of pale yellow viscous liquid product, whichwas purified by alumina gel chromatography, the solvent being chloroformto give 8.6 g (yield: 89%) of the title compound as a colorlesstransparent viscous liquid product.

The physical properties of the product are as follows.

(1) ¹ H-NMR (CDCl₃) δ(ppm): 0.75-2.53 (m, 68H), 5.22-5.30 (m, 2H)

(2) ¹³ C-NMR (CDCl₃) δ(ppm): 26.1, 26.3, 26.5, 26.8, 28.0, 28.1, 28.2,30.9, 32.8, 33.7, 34.2, 34.6, 35.2, 40.7, 43.1, 43.8, 49.0, 52.7, 70.2,174.9

EXAMPLE C4 Bis(3-benzyl-2,2,6,6-tetramethylpiperidin-4-yl) sebacate,Compound C14 which is equal to Compound A1'

The procedure set forth in Example C1 was followed except for the use of8.7 g (35 mmol) of 3-benzyl-4-hydroxy-2,2,6,6-tetramethylpiperidine inplace of 3-cyclohexylmethyl-4-hydroxy-2,2,6,6-tetramethylpiperidine toproduce 10.5 g of pale yellow viscous liquid product, which was purifiedby alumina gel chromatography, the solvent being chloroform to give 8.7g (yield: 88%) of the title compound as a colorless transparent viscousliquid product.

The physical properties of the product are as follows.

(1) ¹ H-NMR (CDCl₃) δ(ppm): 1.02-1.44 (m, 40H), 1.58-1.77 (m, 6H), 1.87(dd, 2H), 2.34 (t, 4H) 2.52-2.63 (m, 2H), 2.76-2.85 (m, 2H), 4.92-5.03(m, 2H), 7.08-7.34 (m, 10H)

(2) ¹³ C-NMR (CDCl₃) δ(ppm): 24.9, 26.8, 29.2, 30.5, 32.8, 33.2, 34.4,34.9, 40.6, 49.3, 49.8, 53.1, 69.8, 126.0, 128.4, 128.9, 140.8, 173.0

EXAMPLE C5 3-Benzyl-2,2,6,6-tetramethylpiperidin-4-yl sebacate, CompoundC4

The procedure set forth in Example C4 was followed except for the use of4.5 g (15 mmol) of methyl sebacate in place of dimethyl sebacate toproduce 8.2 g of pale yellow viscous liquid product, which was purifiedby alumina gel chromatography, the solvent being chloroform to give 7.1g (yield: 92%) of the title compound as a colorless transparent viscousliquid product.

The physical properties of the product are as follows.

(1) ¹ H-NMR (CDCl₃) δ(ppm): 0.88 (s, 3H), 1.03-1.46 (m, 41H), 1.62-1.75(m, 3H), 1.86 (dd, 2H), 1.34 (t, 2H), 2.51-2.62 (m, 1H), 2.74-2.82 (m,1H), 4.91-4.98 (m, 1H), 7.05-7.31 (m, 5H)

(2) ¹³ C-NMR (CDCl₃) δ(ppm): 14.1, 22.7, 25.0, 26.9, 29.3, 29.4, 29.5,29.7, 30.6, 31.9, 32.9, 33.3, 34.5, 34.9, 40.7, 49.1, 50.0, 52.9, 69.8,126.0, 128.4, 128.9, 140.9, 173.0

EXAMPLE C6 Bis(3-benzyl-2,2,6,6-tetramethylpiperidin-4-yl)1,4-cyclohexanedicarboxylate, Compound C10

The procedure set forth in Example C4 was followed except for the use of3.0 g (15 mmol) of dimethyl 1,4-cyclohexanedicarboxylate in place ofdimethyl sebacate to produce 9.3 g of pale yellow viscous liquidproduct, which was purified by alumina gel chromatography, the solventbeing chloroform to give 8.0 g (yield: 85%) of the title compound as acolorless transparent viscous liquid product.

The physical properties of the product are as follows.

(1) ¹ H-NMR (CDCl₃) δ(ppm): 0.95-1.90 (m, 36H), 2.12-2.40 (m, 6H),2.48-2.63 (m, 2H), 2.73-2.85 (m, 2H), 4.92-5.05 (m, 2H), 7.05-7.33 (m,10H)

(2) ¹³ C-NMR (CDCl₃) δ(ppm): 26.3, 26.9, 28.1, 28.2, 28.3, 28.4, 30.7,32.8, 33.2, 34.5, 40.7, 43.1, 49.1, 50.0, 52.9, 70.0, 126.0, 128.5,128.8, 140.8, 174.5

EXAMPLE C7 Bis(3-benzylidene-2,2,6,6-tetramethylpiperidin-4-yl)sebacate, Compound C13

The procedure set forth in Example C1 was followed except for the use of8.6 g (35 mmol) of 3-benzylidene-4-hydroxy-2,2,6,6-tetramethylpiperidinein place of 3-cyclohexylmethyl-4-hydroxy-2,2,6,6-tetramethylpiperidineto produce 9.7 g of pale yellow viscous liquid product, which waspurified by alumina gel chromatography, the solvent being chloroform togive 8.5 g (yield: 87%) of the title compound as a colorless transparentviscous liquid product.

The physical properties of the product are as follows.

(1) ¹ H-NMR (CDCl₃) δ(ppm): 1.06-1.75 (m, 40H), 2.06 (dd, 2H), 2.25 (t,4H), 5.81-5.85 (m, 2H), 6.68 (s, 2H), 7.08-7.34 (m, 2H)

(2) ¹³ C-NMR (CDCl₃) δ(ppm): 24.9, 29.0, 32.3, 32.5, 32.9, 33.4, 34.9,41.0, 48.8, 54.5, 69.1, 127.1, 127.9, 128.3, 128.4, 136.8, 142.8, 172.5

EXAMPLE C8 3-Benzylidene-2,2,6,6-tetramethylpiperidin-4-yl) stearate,Compound C3

The procedure set forth in Example C7 was followed except for the use of4.5 g (15 mmol) of methyl stearate in place of dimethyl sebacate toproduce 7.8 g of pale yellow viscous liquid product, which was purifiedby alumina gel chromatography, the solvent being chloroform to give 6.9g (yield: 96%) of the title compound as a colorless transparent viscousliquid product.

The physical properties of the product are as follows.

(1) ¹ H-NMR (CDCl₃) δ(ppm): 0.88 (t, 3H), 1.11-1.71 (m, 44H), 2.04 (dd,1H), 2.23 (t, 2H), 5.82-5.87 (m, 1H), 6.65 (s, 1H), 7.09-7.32 (m, 5H)

(2) ¹³ C-NMR (CDCl₃) δ(ppm): 14.1, 22.7, 24.9, 29.1, 29.3, 29.4, 29.5,29.7, 31.9, 32.5, 33.0, 33.5, 34.7, 41.0, 48.4, 54.1, 69.0, 126.9,127.6, 128.1, 128.4, 136.8, 143.1, 172.0

EXAMPLE C9 Bis(3-benzylidene-2,2,6,6-tetramethylpiperidin-4-yl)1,4-cyclohexanedicarboxylate, Compound C9

The procedure set forth in Example C7 was followed except for the use of3.0 g (15 mmol) of dimethyl 1,4-cyclohexanedicarboxylate in place ofdimethyl sebacate to produce 9.3 g of pale yellow viscous liquidproduct, which was purified by alumina gel chromatography, the solventbeing chloroform to give 7.7 g (yield: 82%) of the title compound as acolorless transparent viscous liquid product.

The physical properties of the product are as follows.

(1) ¹ H-NMR (CDCl₃) δ(ppm): 1.08-1.57 (m, 30H), 1.65-1.77 (m, 2H),1.96-2.28 (m, 8H), 5.79 (t, 2H), 6.69 (s, 2H), 7.03-7.35 (m, 10H)

(2) ¹³ C-NMR (CDCl₃) δ(ppm): 28.1, 32.5, 32.6, 33.1, 33.6, 41.2, 43.0,48.5, 54.2, 69.4, 127.9, 128.3, 128.4, 136.9, 143.0, 174.1

EVALUATION C1

To 100 parts by weight of powder of polypropylene having an intrinsicviscosity of 1.9 determined at 135° C. in tetralin and a content of theisotactic fraction of 98% were added 0.2 parts by weight of the sampleprepared in Examples C1-C9 and 0.1 part by weight oftetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxymethyl]methane, and the mixture was thoroughly mixed by a mixer, and themixture was kneaded and extruded from an extruder of a cylindertemperature of 260° C. and an extruder diameter of 20 mm into pellets.

The pellets were press-molded at 230° C. into a sheet of 0.5 mm thick toform a test piece, test pieces 1-9.

Another piece was prepared from resin compositions which was the same asthose used in forming test piece 9 except that, in place of thepiperidine derivatives, bis(2,2,6,6-tetramethylpiperidine) sebacate(LS770) was used.

These test pieces were subjected to a photostabilization test by axenone weather-o-meter, Model 65/XW-WR, manufactured by Atlas Corp.under irradiation with light at the black panel temperature of 80° C.until the test piece became deteriorated, and the time required untilthe deterioration was measured and recorded in Table C1 given below.

                  TABLE C1                                                        ______________________________________                                                                      Time until                                                                    deterio-                                        No.   Additive                ration, Hr.                                     ______________________________________                                        1c    --                      100                                             2c    Bis(2,2,6,6-tetramethylpiperidin-4-                                                                   640                                                   yl) sebacate (LS770)                                                    3c    Bis(3-cyclohexylmethyl-2,2,6,6-                                                                       900                                                   tetramethylpiperidin-4-yl) sebacate                                           (Compound C15)                                                          4c    Bis(3-cyclohexylmethyl-1,2,2,6,6-                                                                     920                                                   pentamethylpiperidin-4-yl) sebacate                                           (Compound C16)                                                          5c    Bis(3-cyclohexylmethyl-2,2,6,6-                                                                       900                                                   tetramethylpiperidin-4-yl) 1,4-                                               cyclohexanedicarboxylate                                                      (Compound C11)                                                          6c    Bis(3-benzyl-2,2,6,6-   890                                                   tetramethylpiperidin-4-yl) sebacate                                           (Compound C14)                                                          7c    3-Benzyl-2,2,6,6-       720                                                   tetramethylpiperidin-4-yl stearate                                            (Compound C4)                                                           8c    Bis(3-benzyl-2,2,6,6-   760                                                   tetramethylpiperidin-4-yl) 1,4-                                               cyclohexanedicarboxylate                                                      (Compound C10)                                                          9c    Bis(3-benzylidene-2,2,6,6-                                                                            650                                                   tetramethylpiperidin-4-yl) sebacate                                           (Compound C13)                                                          10c   3-Benzylidene-2,2,6,6-  660                                                   tetramethylpiperidin-4-yl stearate                                            (Compound C3)                                                           11c   Bis(3-benzylidene-2,2,6,6-                                                                            650                                                   tetramethylpiperidin-4-yl) 1,4-                                               cyclohexanedicarboxylate (Compound C9)                                  ______________________________________                                    

As is evident from the results set forth in Table A1, the piperidinederivatives in accordance with the present invention are improvedphotostabilization, namely elongation of the time until thedeterioration.

What is claimed is:
 1. A compound represented by the formula: ##STR70## wherein R¹ indicate a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a benzoyl group, a phenylalkylcarbonyl group, a phenylalkyl group all having 1 to 4 carbon atoms in said alkyl, or an alkylcarbonyl group having 1 to 6 carbon atoms in said alkyl;R² and R^(2') respectively are a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; R³ and R⁴ in combination form a group ═CH--R⁵ wherein R⁵ is either a substituted or non-substituted phenyl group or a substituted or non-substituted cyclohexyl group, the substituent being an alkyl group having 1 to 4 carbon atoms, or a 2-furyl group or a tetrahydrofuryl group, or R³ indicates a hydrogen atom and R⁴ indicates --CH₂ --R⁵ wherein R⁵ is either a substituted to a non-substituted cyclohexyl group, the substituent being an alkyl having 1 to 4 carbon atoms or a tetrahydrofuryl group.
 2. The compound of claim 1, wherein R³ and R⁴ in combination form a benzylidene group or a furfurylidene group.
 3. The compound as claimed in claim 1, wherein R³ is a hydrogen atom and R⁴ is a cyclohexylmethyl group.
 4. The compound of claim 1, wherein R³ and R⁴, in combination form a group ═CH--R⁵, wherein R⁵ is defined as in claim
 1. 